{"name":"Example","author":"John Doe","url":"https://www.mediawiki.org/wiki/Extension:Example","description":"This extension is an example and performs no discernible function","version":"1.5","license-name":"GPL-2.0+","type":"validextensionclass","manifest_version":1}

For example, if your extension is named "Very silly extension that does nothing", you might want to name all your configuration variables to begin $wgVsetdn or $wgVSETDN.
It doesn't really matter what you choose so long as none of the MediaWiki core begins its variables this way and you have done a reasonable job of checking to see that none of the published extensions begin their variables this way.
Users won't take kindly to having to choose between your extension and some other extensions because you chose overlapping variable names.

It is also a good idea to include extensive documentation of any configuration variables in your installation notes.

Note that after calling wfLoadExtension( 'Silly extension that does nothing' ); the global variable $wfBoilerPlateEnableFoo does not exist. If you set the variable, e.g. in LocalSettings.php then the value given in the

"config":{"BoilerPlateEnableFoo":true},

will not be used.

Preparing classes for autoloading

If you choose to use classes to implement your extension, MediaWiki provides a simplified mechanism for helping PHP find the source file where your class is located.
In most cases this should eliminate the need to write your own __autoload($classname) method.

To use MediaWiki's autoloading mechanism, you add entries to the AutoloadClasses field.
The key of each entry is the class name; the value is the file that stores the definition of the class.
For a simple one class extension, the class is usually given the same name as the extension, so your autoloading section might look like this (extension is named MyExtension):

{"AutoloadClasses":{"MyExtension":"MyExtension_body.php"}}

The filename is relative to the directory the extension.json file is in.

Reporting and administration: Extensions that add reporting and administrative capabilities usually do so by adding special pages. For more information see Manual:Special pages.

Article automation and integrity: Extensions that improve the integration between MediaWiki and its backing database or check articles for integrity features, will typically add functions to one of the many hooks that affect the process of creating, editing, renaming, and deleting articles. For more information about these hooks and how to attach your code to them, please see Manual:Hooks.

Look and feel: Extensions that provide a new look and feel to MediaWiki are bundled into skins. For more information about how to write your own skins, see Manual:Skin and Manual:Skinning.

Security: Extensions that limit their use to certain users should integrate with MediaWiki's own permissions system. To learn more about that system, please see Manual:Preventing access. Some extensions also let MediaWiki make use of external authentication mechanisms. For more information, please see AuthPlugin. In addition, if your extension tries to limit readership of certain articles, please check out the gotchas discussed in Security issues with authorization extensions.

Локализация

Localisation – discusses the MediaWiki localisation engine, in particular, there is a list of features that can be localized and some review of the MediaWiki source code classes involved in localization.

While developing, you may want to disable both cache by setting $wgMainCacheType = CACHE_NONE and $wgCacheDirectory = false, otherwise your system message changes may not show up.

If you want your extension to be used on wikis that have a multi-lingual readership, you will need to add localisation support to your extension.

Store messages in <language-key>.json

Store message definitions in a localisation JSON-file, one for each language key your extension is translated in.
The messages are saved with a message key and the message itself using standard JSON format.
Each message id should be lowercase and may not contain spaces.
An example you can find e.g. in extension MobileFrontend.
Here is an example of a minimal JSON file (in this case en.json:

en.json

{"myextension-desc":"Adds the MyExtension great functionality.","myextension-action-message":"This is a test message"}

Store message documentation in qqq.json

The documentation for message keys can be stored in the JSON file for the pseudo language with code qqq.
A documentation of the example above can be:

qqq.json:

{"myextension-desc":"The description of MyExtension used in Extension credits.","myextension-action-message":"Adds 'message' after 'action' triggered by user."}

Define messages

MediaWiki supports parameterized messages and that feature should be used when a message is dependent on information generated at runtime. Parameter placeholders are specified with $n, where n represents the index of the placeholder; e.g.

"mwe-upwiz-api-warning-was-deleted":"There was a file by this name, '$1', but it was deleted and you can not reupload the file. If your file is different, try renaming it."

Define message documentation

Each message you define needs to have an associated message documentation entry Message documentation; in qqq.json e.g.

"uploadwizard-desc":"Description of extension. It refers to [//blog.wikimedia.org/blog/2009/07/02/ford-foundation-awards-300k-grant-for-wikimedia-commons/ this event], i.e. the development was paid with this $300,000 grant."

Load the localisation file

Use wfMessage in PHP

In your setup and implementation code, replace each literal use of the message with a call to wfMessage( $msgID, $param1, $param2, ... ).
In classes that implement IContextSource (as well as some others such as subclasses of SpecialPage), you can use $this->msg( $msgID, $param1, $param2, ... ) instead.
Пример:

wfMessage('myextension-addition','1','2','3')->parse()

Use mw.message in JavaScript

It's possible to use i18n functions in JavaScript too.
Look at Manual:Messages API for details.

Extension types

Extensions can be categorized based on the programming techniques used to achieve their effect.
Most complex extensions will use more than one of these techniques:

Subclassing: MediaWiki expects certain kinds of extensions to be implemented as subclasses of a MediaWiki-provided base class:

Special pages – Subclasses of the SpecialPage class are used to build pages whose content is dynamically generated using a combination of the current system state, user input parameters, and database queries. Both reports and data entry forms can be generated. They are used for both reporting and administration purposes.

Hooks – A technique for injecting custom php code at key points within MediaWiki processing. They are widely used by MediaWiki's parser, its localization engine, its extension management system, and its page maintenance system.

Tag-function associations – XML style tags that are associated with a php function that outputs HTML code. You do not need to limit yourself to formatting the text inside the tags. You don't even need to display it. Many tag extensions use the text as parameters that guide the generation of HTML that embeds google objects, data entry forms, RSS feeds, excerpts from selected wiki articles.

Руководство:Волшебные слова – A technique for mapping a variety of wiki text string to a single id that is associated with a function. Both variables and parser functions use this technique. All text mapped to that id will be replaced with the return value of the function. The mapping between the text strings and the id is stored in the array $magicWords. The interpretation of the id is a somewhat complex process – see Руководство:Волшебные слова for more information.

Руководство:Переменные – Variables are something of a misnomer. They are bits of wikitext that look like templates but have no parameters and have been assigned hard-coded values. Standard wiki markup such as {{PAGENAME}} or {{SITENAME}} are examples of variables. They get their name from the source of their value: a php variable or something that could be assigned to a variable, e.g. a string, a number, an expression, or a function return value.

Support other core versions

There are two widespread conventions for supporting older versions of MediaWiki core:

Master: the master branch of the extension is compatible with as many old versions of core as possible. This results in a maintenance burden (backwards-compatibility hacks need to be kept around for a long time, and changes to the extension need to be tested with several versions of MediaWiki), but sites running old MediaWiki versions benefit from functionality recently added to the extension.

Release branches: release branches of the extension are compatible with matching branches of core, e.g. sites using MediaWiki 1.32 need to use the REL1_32 branch of the extension. (For extensions hosted on gerrit, these branches are automatically created when new versions of MediaWiki are released.) This results in cleaner code and faster development but users on old core versions do not benefit from bugfixes and new features unless they are backported manually.

For extensions that have a compatible license, you can request developer access to the MediaWiki source repositories for extensions. To specify the licence in code and with "license-name" a key should be used to provide it's short name, e.g. "GPL-2.0-or-later" or "MIT" adhering to the list of identifiers at spdx.org.

Publishing

To autocategorize and standardize the documentation of your existing extension, please see Template:Extension.
To add your new extension to this Wiki:

A developer sharing their code in the MediaWiki code repository should expect:

Feedback / Criticism / Code reviews

Review and comments by other developers on things like framework use, security, efficiency and usability.

Developer tweaking

Other developers modifying your submission to improve or clean-up your code to meet new framework classes and methods, coding conventions and translations.

Improved access for wiki sysadmins

If you do decide to put your code on the wiki, another developer may decide to move it to the MediaWiki code repository for easier maintenance. You may then request commit access to continue maintaining it.

Future versions by other developers

New branches of your code being created automatically as new versions of MediaWiki are released. You should backport to these branches if you want to support older versions.

Incorporation of your code into other extensions with duplicate or similar purposes — incorporating the best features from each extension.

Credit

Credit for your work being preserved in future versions — including any merged extensions.

Similarly, you should credit the developers of any extensions whose code you borrow from — especially when performing a merger.

Any developer who is uncomfortable with any of these actions occurring should not host in the code repository. You are still encouraged to create a summary page for your extension on the wiki to let people know about the extension, and where to download it.

Deploying and registering

If you intend to have your extension deployed on Wikimedia sites (including possibly Wikipedia), additional scrutiny is warranted in terms of performance and security. Consult Review queue.

Providing support / collaboration

Extension developers should open an account on Wikimedia's Phabricator, and request a new project for the extension.
This provides a public venue where users can submit issues and suggestions, and you can collaborate with users and other developers to triage bugs and plan features of your extension.

См. также

Extension:Example – implements some example features with extensive inline documentation